सिद्धान्तशिरोमणि: गणिताध्याय (भास्कराचार्य - ग्रहगणित, मध्यमाधिकार व स्पष्टाधिकार सटीक)

369 Rectification of this time, when β is considered as varying will proceed on the same lines as before. Verse 13. Rectification of the times of Sparsa-Sthiti- Khanda and Mōksha-Sthiti-Khanda. From the position of the Moon and that of the Node obtained for the moment of opposition, have to be com- puted their positions for the moment of first contact and those for the moment of last contact. For this, (T × v) / 60 is to be subtracted and added respectively to the positions at the moment of opposition of the Moon and Node, where T is the time of the Sparsa-Sthiti-Khanda, and v the daily motion (of the Moon or the Node as the case may be). From these positions β has to be computed for the moment of first contact and that of last contact, and from this β the time of Sparsa-Sthiti-Khanda and Mōksha-Sthiti- Khanda have to be rectified by the method of successive approximation. Comm. From fig. 75, C₁ N₁ and C₂ N₂ are the dist- ances gained by the Moon over the centre of the shadow so that to get their correct values β₁ and β₂ are to be used and not β. Hence β₁ and β₂ are to be computed using T the time of Sparsa-Sthiti-Khanda and that of the Mōksha- Sthiti-Khanda which are taken to be equal in the first instance. Since T is the time taken as a first approxi- mation, β₁, β₂ are also approximate in the first instance. From these β₁, β₂ T is to be rectified and in this rectifi- cation, we have T₁ and T₂ differing, as the times of Sparsa- Sthiti-Khanda and Mōksha-Sthiti-Khanda. From these rectified times again β₁, β₂ are further to be rectified and from them again T₁, T₂ are to be further rectified. This procedure is to be continued till constant values are obtained for T₁ and T₂. 47